Microorganisms, such as the Gram-positive microorganisms that are members of the genus Bacillus, have been used for large-scale industrial fermentation due, in part, to their ability to secrete their fermentation products into their culture media. Secreted proteins are exported across a cell membrane and a cell wall, and then are subsequently released into the external media.
Indeed, secretion of heterologous polypeptides is a widely used technique in industry. Typically, cells are transformed with a nucleic acid encoding a heterologous polypeptide of interest to be expressed and secreted to produce large quantities of desired polypeptides. In some cases, the chromosomes of host cells are modified to encode such a heterologous polypeptide. Expression and secretion of desired polypeptides has been controlled through genetic manipulation of the polynucleotides that encode the desired proteins. Despite various advances in protein production methods, there remains a need in the art to provide more efficient methods for extracellular protein secretion with the aim to enhance the production of enzymes such as proteases, which find use in the use in various industries, including but not limited to the cleaning, animal feed and textile processing industry.